Objective: Go Girls was a church-based nutrition and physical activity program designed for overweight African-American (AA) adolescent females. Research Methods and Procedures: Ten predominantly middle-socioeconomic churches were randomized to either a high-intensity (20 to 26 sessions) or moderate-intensity (six sessions) culturally tailored behavioral group intervention delivered over 6 months. Each session included an experiential behavioral activity, ∼30 minutes of physical activity, and preparation and tasting of healthy foods. In the high-intensity group, girls also received four to six telephone counseling calls. From the 10 churches, 123 girls completed baseline and 6-month post-test assessments. The primary outcome was BMI; secondary outcomes included waist and hip circumferences, percentage body fat estimated by bioimpedance, serum insulin, glucose, and lipids, and cardiovascular fitness at 6-month follow-up. Selected measures were also collected at 1-year follow-up. Results: At 6-month follow-up, the net difference between the high- and moderate-intensity groups was 0.5 BMI units. This difference was not statistically significant (p = 0.20). There were no significant group differences in secondary outcomes. Girls in the high-intensity condition, however, who attended more than three-quarters of the sessions had significantly lower BMI and percentage body fat relative to girls in the high-intensity group who attended fewer sessions. Findings at 1-year follow-up mirrored those at 6 months. Discussion: We concluded that the intervention was not effective in reducing adiposity, although there were some positive findings among high attenders. Despite the null result, the intervention was generally well received by participants. Future interventions may require greater dose and a more structured dietary change program. Copyright©2005 NAASO.